We propose to study development using the bacterium Myxococcus xanthus as a model system. Our specific objectives are: (a) To characterize protein H, a development specific protein which peaks at the time of cellular aggregation. The purified protein will be analyzed for its amino acid composition and conformation. Antibodies to pure protein H will be prepared and used to study the quantitation, location, and fate of protein H during development. The binding of protein H to receptors will also be studied. (b) To study cell surface changes during development. The outer and inner membranes of M. xanthus will be purified and the protein changes in these fractions analyzed. Abundant newly made proteins will be purified and characterized. (c) To study transcriptional regulation of development. The RNA polymerase will be purified and characterized from vegetative and developmental extracts. The in vivo and in vitro transcription pattern will be analyzed by hybridization to 'Southern blots'. The transcription of specific developmental genes will be studied. The effect of cyclic AMP and glycerol on in vitro transcription will be analyzed. (d) To study DNA binding proteins during development. Extracts of vegetative and developing cells will be used to purify and analyze DNA binding proteins. The effect of purified DNA binding proteins on in vitro transcription will also be determined.